In remote sensing problems where a wavefield encounters a scattering body, the source wavelet can be extracted by calculating surface integrals which involve the incident or scattered wavefield. No knowledge of the scattering body is required. The general formulas require the field and its normal derivative; however, some geometries require only the field. The application of the technique to the acoustic marine seismic problem is explored. This paper demonstrates a problem of interest in hydrocarbon exploration where one observes the "solution" of a PDE and must reconstruct the source.